Smoking is the biggest driver of the worldwide tuberculosis epidemic, and scientists at Trinity College Dublin and St James's Hospital in Ireland have figured out why.
A report recently published in the American Journal of Respiratory and Critical Care Medicine said the research team conducted a study with smokers, ex-smokers and non-smokers. They found that the white blood cells in the lungs of smokers and ex-smokers showed a weakened response to the TB infection. In the smoker's lungs, these cells malfunction and fail to fight the TB bacteria.
"TB remains a huge global health problem, affecting millions worldwide,” Dr. Joseph Keane, the senior author of the study, said. “It has been known for some time that smokers are more susceptible to getting TB and nearly 80 percent of the world's 1 billion smokers live in countries of high TB prevalence. Therefore, while HIV is a key driver of the disease, numerically, smoking is more prevalent than HIV, making smoking the biggest global driver of the TB epidemic."
The study also found that the weakened white blood cells were more susceptible to recurrence of TB infection.
"This study provides evidence which explains the link between smoking and TB and should considerably strengthen anti-smoking efforts to control TB," Keane, a professor of medicine at Trinity and St James's Hospital, said. "However, the widespread emergence of multi-drug resistance TB means we badly need new therapy and vaccine options for TB. We are already applying the findings of this study to develop new treatment options."